The big unproven tale that you lose 75 percent of your body heat through your head is misguided at best. I had always heard the total was 75 percent between your heads, hands and feet, but mostly the myth remains with heat loss through the head. Do you lose 75 percent of body heat through your head?
It’s a Myth that You Lose 75 Percent of Body Heat through Your Head. Even though this has been scientifically proven as a myth, you will still find places on the web where people actually believe this. Some people will believe anything they hear. Yet other times, these myths have been passed down for generations by reputable sources.
Where Did this Myth Begin? Most likely, the myth that you lose 75 percent of body heat through your head started from a study the U.S. Army performed for the 1970 Manual as discussed in a BMJ article.
The problems with this study were that participants were dressed in arctic survival suits with only their heads exposed. In this case, more heat would be lost through the head. If participants were subjected to cold dressed only in bathing suits, it is estimated the heat loss through the head would only be at ten percent.
How Does Your Body Lose the Most Heat? Your body loses most of its heat through skin, so unprotected skin would lose heat in the cold. Your head accounts for about seven percent of total skin area, so you would lose about seven percent body heat through the head. However, it stand to reason you would lose less total body heat by wearing a hat.
This holds true for any part of your body. If it is cold, cover it up. The greater area of skin exposed to cold, the greater percentage of heat will be lost. The greater percentage of skin covered, the less total body heat will be lost.
Wet or Dry Conditions Can Affect the Rate at Which Body Heat is Lost. If your body is wet in addition to being cold, you will lose heat faster than if you are dry. Heat loss through the head is still only estimated to be at seven percent according to a study published in the Journal of Applied Physiology.
Additional Points Regarding Loss of Body Heat. There is also the saying that says if your feet are cold to wear a hat. While adding the protection of a hat will keep you warmer by preventing heat loss through your scalp, it will do nothing to help the heat lost through the feet.
One point to consider is that it is believed that hypothermia victims will indeed lose more heat through their heads. This is explained in the Wilderness Medicine Newsletter.
Do You Lose 75 percent of Body Heat through Your Head? This is a myth. When going out into the cold, the best way to preserve body heat is to keep all skin from being exposed. If you are not wearing gloves or shoes, a hat will keep in body heat, but not because you lose 75 percent of body heat through your head.
Rachel C. Vreeman and Aaron E. Carroll; Festive medical myths; BMJ
Thea Pretorins, et al.; Thermal effects of whole head submersion in cold water on nonshivering humans; Journal of Applied Physiology
Wilderness Medicine Newsletter; Heat Loss Through the Head and Hypothermia